Wavelength division multiplexing module

ABSTRACT

A telecommunications module includes a main housing portion and a cover, the main housing portion defining a first sidewall, a front wall, a rear wall, a top wall, and a bottom wall, the cover defining a second sidewall when mounted on the main housing portion. An optical component located within the module receives an input signal from a signal input location of the housing and outputs an output signal toward a signal output location on the front wall. The telecommunications module is configured such that the signal input location can be selected to be either on the front wall or the rear wall of the main housing. The cover defines a protrusion extending from the second sidewall toward the main housing portion, the protrusion being selectively breakable to expose a recess on the front wall of the main housing portion that defines a signal input location.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 13/724,625,filed Dec. 21, 2012, now U.S. Pat. No. , which is a continuation ofapplication Ser. No. 13/021,286, filed Feb. 4, 2011, now U.S. Pat. No.8,340,491, which is a continuation of application Ser. No. 12/058,152,filed Mar. 28, 2008, now U.S. Pat. No. 7,885,505, which is acontinuation-in-part of application Ser. No. 11/975,905, filed Oct. 22,2007, now U.S. Pat. No. 7,536,075, which applications are incorporatedherein by reference in their entirety.

FIELD

The present disclosure generally relates to fiber optictelecommunications equipment. More specifically, the present disclosurerelates to fiber optic modules and chassis for holding fiber opticmodules.

BACKGROUND

In fiber optic telecommunications systems, it is common for opticalfibers of transmission cables to be split into multiple strands, eitherby optical splitting of a signal carried by a single stranded cable orby fanning out the individual fibers of a multi-strand cable. Further,when such systems are installed, it is known to provide excess capacityin the installations to support future growth and utilization of thefibers. Often in these installations, modules including splitters orfanouts are used to provide the connection between transmission fibersand customer fibers. To reduce the cost and complexity of the initialinstallation and still provide options for future expansion, a modulemounting chassis capable of mounting multiple modules may be used insuch an installation.

While the chassis may accept several modules, the initial installationmay only include fewer modules mounted in the chassis, or enough toserve current needs. These chassis may be configured with limited accessto one or more sides, or may be mounted in cramped locations. Inaddition, some of these chassis may be pre-configured with the maximumcapacity of transmission cables to accommodate and link to modules whichmay be installed in the future. Since it is desirable to have access tocomponents within the chassis for cleaning during the installation of anew module, some provision or feature of the chassis will desirablypermit a user to access and clean the connectors of thesepre-connectorized and pre-installed transmission cables.

It is also desirable for the chassis to be configured to ensure thatmodules are installed correctly and aligned with other components withinthe chassis to mate with the pre-connectorized and pre-installedtransmission cables.

In fiber-optic communications, it is also common for optical signals oftransmission cables to be multiplexed. Wavelength division multiplexing(WDM) is a technology which multiplexes multiple optical carrier signalson a single optical fiber by using different wavelengths of laser lightto carry different signals. This allows for a multiplication incapacity, in addition to making it possible to perform bidirectionalcommunications over one strand of fiber.

A WDM system uses a multiplexer at the transmitter to join signalstogether and a demultiplexer at the receiver to split them apart. Withthe right type of fiber, it is possible to have a device that does bothsimultaneously, and can function as an optical add-drop multiplexer. WDMsystems allow expansion of the capacity of the network without layingmore fiber.

WDM systems are divided in different wavelength patterns: 1)conventional WDM; 2) dense WDM (DWDM); and 3) coarse WDM (CWDM).Conventional WDM systems may provide up to 16 channels in the 3rdtransmission window (C-band) of silica fibers around 1550 nm with achannel spacing of 100 GHz. DWDM may use the same transmission windowbut with less channel spacing enabling up to 31 channels with 50 GHzspacing and 62 channels with 25 GHz spacing, sometimes called ultradense WDM. CWDM in contrast to conventional WDM and DWDM uses increasedchannel spacing to allow less sophisticated and thus less expensivetransceiver designs. WDM, DWDM and CWDM are based on the same concept ofusing multiple wavelengths of light on a single fiber, but differ in thespacing of the wavelengths, number of channels, and the ability toamplify the multiplexed signals in the optical space.

In the telecommunications industry, it would be desirable to packageoptical add-drop multiplexers in a modular form to allow for futureexpansion of service to customers. It would also be desirable to reducethe cost and complexity of the installation and integration of themultiplexers into telecommunications systems and allow for easy accessto the multiplexers.

SUMMARY

The present invention relates to a telecommunications assembly includinga chassis and a plurality of modules mounted within the chassis. Withinan interior of each of the modules is located a fiber optic component.In one embodiment, the fiber optic component may be a fiber opticsplitter. In another embodiment, the fiber optic component may be afiber optic division multiplexer/demultiplexer. The modules may includeone or more signal input locations at the rear of the module housing orat the front of the module housing adjacent signal output locations. Inthe case of a multiplexer/demultiplexer, the signal input locations alsoact as signal output locations since the module may be configured toboth demultiplex signals coming in and multiplex signals going out ofthe module. When the module is used as a fiber optic divisionmultiplexer/demultiplexer module, the multiplexer/demultiplexer, as areceiver, is configured to demultiplex multiple optical carrier signalscarried by the single input optical fiber into different wavelengths oflaserlight as customer output signals. As a transmitter, themultiplexer/demultiplexer is configured to multiplex the customersignals, which are different wavelengths of laserlight, and combine theminto a single optical fiber to be outputted from the module.

According to another aspect of the present disclosure, the module may beconfigured to include either front signal input locations or rear signalinput locations. According to one embodiment, the cover of the modulemay include at least one tab that fits within a recess defined at afront wall of the main housing portion of the module. The tab and therecess may be used to correctly orient the cover with respect to themain housing. The recess, however, may also define a signal inputlocation, wherein terminated fiber optic cables may be accommodated byand received within the recess. The tab of the cover previously used tocover the recess of the module housing may be cut or broken to anappropriate length to accommodate the terminated cables entering themodule.

The present disclosure further relates to a method of mounting atelecommunications module within a telecommunications chassis.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the description, illustrate several aspects of the inventivefeatures and together with the detailed description, serve to explainthe principles of the disclosure. A brief description of the drawings isas follows:

FIG. 1 is a rear perspective view of a telecommunications assembly witha plurality of fiber optic splitter modules installed within a chassis,with one of the adapter assemblies exploded out of thetelecommunications assembly;

FIG. 2 is a top view of the telecommunications assembly of FIG. 1;

FIG. 3 is a front view of the telecommunications assembly of FIG. 1;

FIG. 4 is a rear view of the telecommunications assembly of FIG. 1;

FIG. 5 is a left side view of the telecommunications assembly of FIG. 1;

FIG. 6 is a right side view of the telecommunications assembly of FIG.1;

FIG. 6A illustrates a front perspective of the chassis of thetelecommunications assembly of FIG. 1, shown with one fiber opticsplitter module mounted therein;

FIG. 7 is a close-up view of the telecommunications assembly of FIG. 1showing the adapter assembly exploded out of the telecommunicationsassembly;

FIG. 8 is a front perspective view of one of the adapter assemblies ofFIG. 1;

FIG. 9 is a rear perspective view of the adapter assembly of FIG. 8;

FIG. 10 is a right side view of the adapter assembly of FIG. 8;

FIG. 11 is a left side view of the adapter assembly of FIG. 8;

FIG. 12 is a front view of the adapter assembly of FIG. 8;

FIG. 13 is a rear view of the adapter assembly of FIG. 8;

FIG. 14 is a top view of the adapter assembly of FIG. 8;

FIG. 15 is a bottom view of the adapter assembly of FIG. 8;

FIG. 16 is a right side view of one of the fiber optic splitter modulesof FIG. 1, shown with an adapter assembly mounted thereon;

FIG. 17 is a left side view of the fiber optic splitter module andadapter assembly of FIG. 16;

FIG. 18 is a front view of the fiber optic splitter module and adapterassembly of FIG. 16;

FIG. 19 is a rear view of the fiber optic splitter module and adapterassembly of FIG. 16;

FIG. 20 is a front perspective view of the fiber optic splitter moduleof FIG. 16, shown in isolation without an adapter assembly mountedthereon;

FIG. 21 is a rear perspective view of the fiber optic splitter module ofFIG. 20;

FIG. 22 is an exploded view of the fiber optic splitter module of FIG.16, shown with the adapter assembly exploded from the fiber opticsplitter module;

FIG. 23 is a left side view of the fiber optic splitter module of FIG.20;

FIG. 24 is a right side view of the fiber optic splitter module of FIG.20;

FIG. 25 is a front view of the fiber optic splitter module of FIG. 20;

FIG. 26 is a rear view of the fiber optic splitter module of FIG. 20;

FIG. 27 is a top view of the fiber optic splitter module of FIG. 20;

FIG. 28 is a bottom view of the fiber optic splitter module of FIG. 20;

FIG. 29 is a right side view of the fiber optic splitter module of FIG.20, shown without a cover exposing the interior features of the fiberoptic splitter module including routing of a fiber optic cable withinthe fiber optic splitter module;

FIG. 30 is a cross-sectional view taken along section line 30-30 of FIG.29;

FIG. 31 illustrates a fiber optic splitter module partially insertedwithin the chassis of FIG. 1, the chassis including an adapter assemblymounted thereon, the fiber optic splitter module shown in a positionprior to the connectors of the splitter module having contacted a shieldlocated within the chassis;

FIG. 32 illustrates the fiber optic splitter module of FIG. 31, shown ina position within the chassis with the connectors of the fiber opticsplitter module making initial contact with the shield located withinthe chassis;

FIG. 33 illustrates the fiber optic splitter module of FIG. 31, shown ina fully inserted position within the chassis;

FIG. 34 is a side cross-sectional view of the fiber optic splittermodule of FIG. 32 within the chassis, taken through the center of thefiber optic splitter module;

FIG. 35 is a side cross-sectional view of the fiber optic splittermodule of FIG. 33 within the chassis, taken through the center of thefiber optic splitter module;

FIG. 36 illustrates a front perspective view of a fiber opticwavelength-division multiplexing (WDM) module having features that areexamples of inventive aspects in accordance with the present disclosure,the WDM module configured to be inserted within the chassis that isshown in FIGS. 1-6;

FIG. 37 is a rear perspective view of the WDM module of FIG. 36;

FIG. 38 is an exploded view of the WDM module of FIG. 36;

FIG. 39 is a right side view of the WDM module of FIG. 36, shown withouta cover exposing the interior features of the module including routingof fiber optic cables within the module;

FIG. 40 is a front perspective view of the main housing portion of theWDM module of FIG. 36, the main housing portion shown without theinternal components mounted therein;

FIG. 41 is a rear perspective view of the main housing portion of FIG.40;

FIG. 42 is a right side view of the main housing portion of FIG. 40;

FIG. 43 is a left side view of the main housing portion of FIG. 40;

FIG. 44 is a front view of the main housing portion of FIG. 40;

FIG. 45 is a cross-sectional view of the main housing portion of FIG. 40taken along line 45-45 of FIG. 43;

FIG. 46 is a rear perspective view of the cover of the WDM module ofFIG. 36;

FIG. 47 is a right side view of the cover of FIG. 46;

FIG. 48 is a left side view of the cover of FIG. 46;

FIG. 49 illustrates a front perspective view of the WDM module of FIGS.36-48, the module configured as a front-input module having two frontsignal input locations that are configured in a stacked arrangementextending from the right side to the left side of the module;

FIG. 50 is a rear perspective view of the WDM module of FIG. 49;

FIG. 51 an exploded view of the WDM module of FIG. 49;

FIG. 52 is a partially assembled view of the WDM module of FIG. 51;

FIG. 53 illustrates a front perspective view of the WDM module of FIG.49, with the module configured as a front-input module having one frontsignal input location;

FIG. 54 is a rear perspective view of the WDM module of FIG. 53;

FIG. 55 an exploded view of the WDM module of FIG. 53;

FIG. 56 is a partially assembled view of the WDM module of FIG. 55;

FIG. 57 is an exploded view of a front input connection configured foruse with a module having a front-input arrangement such as the WDMmodule shown in FIGS. 49-56;

FIG. 58 illustrates the input connection of FIG. 57 in a fully assembledconfiguration;

FIG. 59 is an exploded view of an alternative embodiment of a fiberoptic splitter module having features that are examples of inventiveaspects in accordance with the present disclosure, the fiber opticsplitter module including front signal input locations that areconfigured in a side by side arrangement along the direction extendingfrom the top to the bottom of the module;

FIG. 60 is a left side view of the fiber optic splitter module of FIG.59;

FIG. 61 is a right side view of the fiber optic splitter module of FIG.59;

FIG. 62 is a right side view of the fiber optic splitter module of FIG.59, shown without the cover exposing the interior features of the fiberoptic splitter module including routing of a fiber optic cable withinthe fiber optic splitter module;

FIG. 63 is a right side view of another embodiment of a fiber opticsplitter module having features that are examples of inventive aspectsin accordance with the present disclosure, the fiber optic splittermodule including front signal input locations that are configured in astacked arrangement extending from the right side to the left side ofthe module, similar to the module shown in FIGS. 49-56, the fiber opticsplitter module shown in combination with a prior art fiber opticadapter module configured to hold a plurality of fiber optic adapters;and

FIG. 64 is a bottom view of the fiber optic splitter module of FIG. 63.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary aspects of the presentinvention which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or similar parts.

FIGS. 1-7 illustrate a telecommunications assembly 10 that includes atelecommunications chassis 12 and a plurality of fiber optic splittermodules 14 adapted to be mounted within chassis 12. Fiber optic splittermodules 14 are configured to be slidably inserted within chassis 12 andbe optically coupled to adapter assemblies 16 mounted within chassis 12.Adapter assemblies 16 mounted within chassis 12 form connectionlocations between connectors terminated to an incoming fiber optic cableand connectors of splitter modules 14 as will be discussed in furtherdetail below.

Still referring to FIGS. 1-7, chassis 12 includes a top wall 18 and abottom wall 20 extending between a pair of opposing transversesidewalls, 22, 24. Chassis 12 includes an opening 26 through a rear side28 of chassis 12 and an opening 30 through a front side 32 of chassis12. Fiber optic splitter modules 14 are inserted into chassis 12 throughfront opening 30. Adapter assemblies 16 are inserted through and mountedadjacent rear opening 26 of chassis 12. Sidewalls 22, 24, each include acut-out 34 extending from front opening 30 toward rear side 28. Splittermodules 14 mounted within chassis 12 are visible through cut-out 34.Sidewalls 22, 24 of chassis 12 also define an inset portion 36 at rearside 28 of chassis 12 to facilitate access to adapter assemblies 16.

In FIG. 1, chassis 12 is shown with eight fiber optic splitter modules14 mounted thereon. It should be noted that in other embodiments, thechassis may be sized to hold a larger or a smaller number of splittermodules. As will be described further below, it should be noted that thechassis may hold modules other than splitter modules, such as moduleshousing fiber optic multiplexers. A fiber optic splitter is only oneexample of telecommunications equipment that might be supported by themodule. Still referring to FIGS. 1-7, chassis 12 includes a plurality ofmounting locations 38 for slidably receiving splitter modules 14. Eachmounting location 38 defines a slot 40 adjacent top wall 18 and a slot42 adjacent bottom wall 20 of chassis 12. Slots 42 adjacent bottom wall20 are visible in FIG. 1. Slots 40 adjacent top wall 18 are illustratedin FIG. 6A. Slots 40, 42 extend from front 32 of chassis 12 to rear 28of chassis 12. Slots 40, 42 are configured to receive mounting flanges44, 46 of splitter modules 14 as shown in FIG. 6A to align modules 14with other components within chassis 12 (e.g., adapters of the adapterassemblies) to mate with pre-connectorized and/or pre-installedtransmission cables.

Slots 40 defined underneath top wall 18 of chassis 12 are deeper thanslots 42 defined at bottom wall 20 of chassis 12. The depth of slots 40,42 are configured to accommodate the different sized flanges 44, 46 thatare defined at top and bottom walls of splitter modules 14. In thismanner, slots 40, 42 and mounting flanges 44, 46 of fiber optic splittermodules 14 provide a keying system to ensure that modules 14 areinserted into chassis 12 in the correct orientation.

Slots 40 underneath top wall 18 of chassis 12 are defined between aplurality of bulkheads 48 (please see FIG. 6A). Bulkheads 48 extend fromfront 32 of chassis 12 to rear 28 of chassis 12. At front end 32 ofchassis 12, each bulkhead 48 defines a downwardly extending front lip 50(FIG. 35) which interlocks with a resiliently deformable latch 52 (e.g.,cantilever arm) of splitter module 14 to hold splitter module 14 inplace within chassis 12, as will be discussed in further detail below.

Referring to FIGS. 1 and 7, at rear end 28 of chassis 12, each bulkhead48 defines a rear face 54 with a fastener hole 56 for receiving afastener 58 (e.g., a thumbscrew) of an adapter assembly 16 for mountingadapter assembly 16 to chassis 12. In the embodiment shown, fastenerhole 56 is threaded to receive a screw-type fastener. It should be notedthat in other embodiments, other types of fastening structures may beused to mount adapter assembly 16 to rear 28 of chassis 12.

Adjacent rear end 28, each bulkhead 48 also includes a horizontal slot60 and a vertical slot 62 that complement the shape of adapter assembly16 to slidably receive adapter assembly 16.

FIGS. 8-15 illustrate adapter assembly 16 according to the invention.Adapter assemblies 16 form connection locations between the connectorsterminated to an incoming fiber optic cable and the connectors ofsplitter modules 14 mounted within chassis 12.

Referring to FIGS. 8-15, adapter assembly 16 includes two integratedadapters 64 formed as a part of a unitary housing 66. In otherembodiments, other number of adapters are also possible. Each adapter 64of adapter assembly 16 includes a front end 68 and a rear end 70. Frontend 68 of each adapter 64 receives a connector of fiber optic splittermodule 14 and rear end 70 receives a connector terminated to an incomingfiber optic cable.

Adapter assembly housing 66 includes a chassis-mounting slide 72extending from a top 74 of housing 66, which is received within chassis12 through rear end 28. Slide 72 defines a horizontal portion 76 and avertical portion 78. Horizontal portion 76 is configured to be slidablyreceived within horizontal slot 60 of bulkhead 48 and vertical portion78 is configured to be slidably received within vertical slot 62 ofbulkhead 48.

Chassis-mounting slide 72 includes a pair of flanges 80 for supporting afastener 58 for securing adapter assembly 16 to chassis 12. As discussedearlier, fastener 58 is positioned within an opening 56 defined by rearface 54 of bulkheads 48 located underneath top wall 18 of chassis 12.Fastener 58 is preferably a captive fastener. In the embodiment of theadapter assembly shown in the FIGS., fastener 58 is a thumbscrew. Inother embodiments, other types of fasteners may be used.

Fastener 58 is rotated to threadingly couple the adapter assembly 16 tothe bulkheads 48. Fastener 58 is also configured such that it is able toprovide adapter assembly 16 with a predetermined amount of horizontalfloat relative to the chassis 12 once mounted thereon. As illustrated inFIGS. 8-14, the fastener 58 of the adapter assembly 16 includes a flange81. The fastener 58 is able to move horizontally within the flanges 80relative to the adapter assembly housing 66. As shown in FIG. 35, oncemounted to the chassis 12, the adapter assembly housing 66 is able tofloat or move horizontally with respect to the fastener 58 betweenflange 81 and the rear face of the bulkhead 48. For example, in FIG. 35,adapter assembly 16 is shown to be able to move or float a distance of Atoward the rear end of chassis 12. In this manner, when a splittermodule 14 is slidably pulled out of chassis 12 during disengagement,adapter assembly 16 is able to horizontally float a distance A towardssplitter module 14 as the engaged connector 118 of splitter module 14pulls on adapter 64 of adapter assembly 16. In this manner, adapterassembly 16 is provided with a certain amount of horizontal float whenbeing engaged to and disengaged from splitter module 14.

Elements of each adapter 64 are positioned through a side opening intoadapter recesses formed within the adapter assembly housing 66. Theelements for each adapter 64 include a ferrule alignment sleeve and apair of inner housing halves. These elements are placed within recessesin manner similar to that shown in commonly-owned U.S. Pat. No.5,317,663, issued May 20, 1993, entitled ONE-PIECE SC ADAPTER, thedisclosure of which is incorporated herein by reference. A panel closesopening and secures the elements within each adapter 64. Adapters 64shown are for SC style connectors, although other types, styles andformats of adapters may be used within the scope of the presentdisclosure and connectors to mate with these alternative adapters.

A grip extension 218 (FIGS. 1 and 7) may be used with connectors 118coupled to rear 70 of adapters 64 of adapter assembly 16. Grip extension218 is designed to add length to the outer housing 150 of a connector118 to facilitate access to individual connectors 118 in denseenvironments such as the telecommunications assembly 10. Grip extensionis preferably first mounted over a cable before the cable is terminatedto a connector 118. Once the connector 118 is terminated to the cable,grip extension 218 is slid over the boot portion 220 of the connectorand mounted to the outer housing 150 of connector 118 as shown in FIG.7.

In FIGS. 16-19, adapter assembly 16 is shown mounted to a fiber opticsplitter module 14, outside of chassis 12.

FIGS. 20-30 illustrate one of the fiber optic splitter modules 14according to the invention. Referring to FIGS. 20-30, the fiber opticsplitter module 14 includes a splitter module housing 92. Splittermodule housing 92 includes a main housing portion 94 and a removablecover 96. Main housing portion 94 includes a first transverse sidewall98 extending between a top wall 100, a bottom wall 102, a rear wall 104,and a front wall 106. Removable cover 96 defines a second transversewall 108 of splitter module housing 92 and closes off the open side ofmodule main housing 94.

Cover 96 is mounted to main housing portion 94 by fasteners (not shown)through fastener mounts 110 defined on main housing portion 94. Cover 96extends beyond first transverse sidewall 98 to form a top mountingflange 44 and a bottom mounting flange 46 of splitter module 14.Referring to FIGS. 23, 25, and 26, as discussed previously, bottomflange 46 of splitter module housing 92 and the corresponding slot 42 onchassis 12 are smaller in size than top flange 44 and the correspondingtop slot 40 on chassis 12. Bottom slot 42 is sized so that, while bottomflange 46 may be received within slot 42, the larger top flange 44 willnot fit. This ensures that modules 14 are positioned within frontopening 30 in a particular desired orientation. Similar flanges aredescribed in commonly-owned U.S. Pat. No. 5,363,465, issued Nov. 8,1994, entitled FIBER OPTIC CONNECTOR MODULE, the disclosure of which isincorporated herein by reference. In this manner, fiber optic modules 14are oriented correctly to be coupled to adapter assemblies 16 mountedadjacent rear 28 of chassis 12 at each mounting location 38.

Rear wall 104 of main housing portion 94 includes a curved portion 112configured to provide bend radius protection to cables within interior114. Rear wall 104 of main housing 92 also includes an inset portion116. A pair of fiber optic connectors 118 positioned at inset portion116 protrude rearwardly from rear wall 104 for mating with fiber opticadapters 64 of adapter assemblies 16 mounted within chassis 12.

As shown in FIGS. 5 and 6, front wall 106 of module main housing 94 isangled with regard to front opening 30 of chassis 12, which may aid inthe direction of cables exiting module 14 toward a desired location. Inother embodiments, front walls 106 could be made generally parallel tofront 32 of chassis 12 within the scope of the present disclosure.

Each module 14 includes two cable exits 120 extending from front wall106 of module main housing 94. As shown in FIG. 22, cable exits 120 areslidably mounted to main housing 94 of module 14 and captured by cover96 of module 14 when cover 96 is mounted to main housing 94. Cable exits120 define a protruding rear lip 122 that is slidably inserted intoslots 124 defined around front apertures 126 for accommodating cableexits 120. Cover 96 also includes slits 128 that receive rear lips 122of the cable exits 120 to capture cable exits 120. Cable exits 120permit telecommunications cables within module 14 to be directed outsideof module 14. Cable exits 120 are preferably sized thin enough to fitwithin the profile of the fiber optic splitter module 14, as shown inFIG. 25, to preserve the density of the telecommunications assembly 10.

Main housing 94 includes an integrally formed flexible latch 52 (i.e.,cantilever arm) that is adapted to engage a portion of chassis 12 tohold module 14 within front opening 30 of chassis 12. Flexible latch 52also deflects to permit withdrawal of module 14 from chassis 12.

Still referring to FIGS. 20-30, latch 52 of module 14 includes a fingergrip tab 130, a front latching tab 132 and a rear latching tab 134.Front latching tab 132 and rear latching tab 134 define a recess 136thereinbetween. Rear latching tab 134 includes a ramped face 138 thatcauses latch 52 to elastically deflect down when module 14 is beinginserted into chassis 12. Rear latching tab 134 also includes a squareface 140 that opposes a square face 142 of front latching tab 132.

Front lip 50 of bulkhead 48 at mounting location 38 of chassis 12 iscaptured in recess 136 between the two latching tabs 132, 134 to holdmodule 14 in place within chassis 12. During insertion, as front lip 50of bulkhead 48 clears ramped rear tab 134 and is captured in recess 136between the two latching tabs 132, 134, latch 52 flexes back upwardly.Recess 136 between the two tabs 132, 134 of latch 52 allows for acertain amount of horizontal float for splitter module 14 within chassis12, as will be discussed in further detail below.

The removal of module 14 from chassis 12 is performed by pressing latch52 downwardly to clear the square face 140 of rear tab 134 from lip 50and sliding module 14 away from chassis 12. Module 14 includes a fixedgrip tab 144 opposing and adjacent to flexible latch 52 to aid removalof module 14 from chassis 12. Fixed grip tab 144 is formed as a part offront wall 106 of module 14. Fixed grip tab 144 is preferably positionedon module 14 opposite latch 52 so that a user may apply opposing forceon latch 52 and fixed grip tab 144 to securely grasp module 14 andremove it from chassis 12. Fixed grip tab 144 is preferably positionedon module 14 close enough to latch 52 so that a user may be apply theforce with two adjacent fingers of the hand.

FIG. 22 shows an exploded view of fiber optic splitter module 14illustrating the internal components of module 14. Fiber optic splittermodule 14 is shown in FIG. 22 with adapter assembly 16 exploded frommodule 14.

Within interior 114 of main housing 94, splitter module 14 includes afirst radius limiter 146 adjacent curved portion 122 of rear wall 104 ofmain housing 94. Splitter module 14 includes a second radius limiter 148adjacent front wall 106 of housing 94 near cable exits 120. Connectors118 of splitter module 14 are slidably inserted into opposing slots 154formed in apertures 156 at the rear wall 104. Connectors 118 project outfrom rear wall 104 at inset portion 116 of rear wall 104. Outer housings150 of connectors 118 include transverse flanges 152 that are receivedwithin the opposing slots 154 formed in apertures 156 that accommodatethe connectors 118. Once slidably inserted, connectors 118 are capturedwithin housing 92 by cover 96.

Adjacent bottom wall 102 of main housing 94 within interior 114 is anoptical component 158 such as a fiber optic splitter or a fan-out.Optical component 158 is held against the interior of bottom wall 102 bya clamp 160 (i.e., bracket). Clamp 160 is mounted to a clamp mount 162defined on splitter module main housing 94 with fasteners (not shown).In the embodiment of the housing 94 shown in the FIGS., clamp mount 162includes two pairs of mounting holes 164, 166. Either the upper set ofholes 164 or the lower set of holes 166 are utilized depending upon thesize of the clamp that will be used to hold optical component 158against bottom wall 102. It should be noted that different opticalcomponents may have different thicknesses and may require the use ofdifferent sized clamps for holding the optical components in place. Incertain embodiments, two optical components that are stacked on top ofanother may be used, in which case, a smaller clamp would be used tohold the two optical components in place.

Optical component 158 is offset from the interior side of firsttransverse sidewall 98 by a set of cable management structures 168. Inthe embodiment of the module 14 illustrated, the set of cable managementstructures 168 are elongate structures 170 defining cable managementslits 172 therein between. When optical component 158 is held in place,cables can be routed through slits 172 between optical component 158 andthe interior of first transverse wall 98 (please see FIGS. 29 and 30).

Splitter module main housing 94 also includes integrally formed crimpholders 174 (e.g., slots) adjacent front wall 106 of housing 94underneath second radius limiter 148. Crimp elements 176 crimped to theends of cables that are split by optical component 158 are slidablyreceived into crimp holders 174 as shown in FIGS. 22 and 29. Crimpelements 176 define square flanges 175 between which is defined arecessed portion 177. The crimp holders 174 include complementarystructure to the crimp elements such that once the crimp elements 176are slidably inserted into the crimp holders 174, the crimp elements 176are prevented from moving in a longitudinal direction due to the flanges175. Once slidably inserted, crimp elements 176 are held in place bycover 96 that is mounted to splitter module main housing 94. In theembodiment shown, there are nine crimp holding slots 174, each one beingable to accommodate up to four crimp elements 176. Other numbers arepossible. Other complementary shapes between the crimp elements and thecrimp holding slots are also possible to provide a slidable fit and toprevent axial movement of the crimp elements once inserted therein thecrimp holders.

FIG. 29 shows fiber optic splitter module 14 without a cover 96 exposingthe interior features of fiber optic splitter module 14 includingrouting of a fiber optic cable within fiber optic splitter module 14.FIG. 30 illustrates a cross-sectional view taken along section line30-30 of FIG. 29.

As shown in FIG. 29, a first cable 178 extends from connector 118 towardoptical component 158, mounted within module housing 92. Opticalcomponent 158, as previously discussed, may be a splitter or a fan-outor another type of optical component. In the embodiment shown, opticalcomponent 158 is a fiber optic splitter that splits the signal of asingle strand to a plurality of secondary signals. In anotherembodiment, first cable 178 may be a multi-strand fiber cable with aplurality of strands of optical fiber and optical component may be afanout to separate the individual strands into each of a plurality ofsecond cables.

First cable 178, as it extends toward optical component 158, is insertedthrough slits 172 (see FIGS. 22, 29, and 30) located between opticalcomponent 158 and the inner side of first transverse sidewall 98 ofmodule housing 94 and looped around first radius limiter 146 and thenaround second radius limiter 148 before being received by opticalcomponent 158. Second cables 180 extend from optical component 158 andare looped again all the way around first radius limiter 146 beforeheading toward crimp holders 174. From crimp holders 174, cables (notshown) crimped to the other ends of the crimps 176 exit the modulethrough module exits 120.

An outside cable (not shown) may extend to rear end 70 of an adapter 64of adapter assembly 16 and be terminated by a connector (not shown inFIG. 29) that is optically connected to connector 118 of module 14through adapter 64 once module 14 is inserted within chassis 12. Itshould be noted that the routing of the fiber optic cables within module14 as shown in FIGS. 29 and 30 is only one example and other ways ofrouting the cables within the module are possible.

The embodiment of the fiber optic splitter module 14 shown in the FIGS.is configured such that it can accommodate reduced bend radius fiber. Areduced bend-radius fiber may have a bend radius of about 15 mm whereasa non-reduced bend-radius fiber may have a bend radius of about 30 mm.

Similar fiber optic splitter modules are described in commonly-ownedU.S. patent application Ser. No. 10/980,978 (filed Nov. 3, 2004,entitled FIBER OPTIC MODULE AND SYSTEM INCLUDING REAR CONNECTORS); Ser.No. 11/138,063 (filed May 25, 2005, entitled FIBER OPTIC SPLITTERMODULE); Ser. No. 11/138,889 (filed May 25, 2005, entitled FIBER OPTICADAPTER MODULE); and Ser. No. 11/215,837 (filed Aug. 29, 2005, entitledFIBER OPTIC SPLITTER MODULE WITH CONNECTOR ACCESS), the disclosures ofwhich are incorporated herein by reference.

The insertion of a splitter module 14 into chassis 12 is illustrated inFIGS. 31-35. Referring to FIGS. 31-35, insertion of fiber optic module12 into front opening 30 of chassis 12 begins the mating of module 14 tochassis 12 and to adapters 64 of adapter assembly 16. Top flanges engage44 top slots 40 and bottom flanges 46 engages bottom slots 42 of chassis12 as module 14 is inserted.

Still referring to FIGS. 31-35, chassis 12 includes a flexible shield182 in each mounting location 38. Shield 182 is adapted to preventprotection against accidental exposure to light. Shield 182 ispositioned in front end 68 of each adapter 64 of adapter assembly 16.Before a splitter module 14 is placed in an associated mounting location38, if a connectorized cable that is connected to an adapter 64 ofadapter assembly 16 is illuminated and transmitting light signals,shield 182 will prevent accidental exposure to these signals which mightdamage eyes or other sensitive organs, or nearby communicationsequipment. The insertion of splitter module 14 pushes shield 182 out ofthe way as illustrated in FIGS. 31-33.

Shield 182 is deflected by module 14 as module 14 is inserted throughfront opening 30 so that connectors 118 of module 14 can mate withadapters 64 of adapter assemblies 16. Shield 182 is preferably made of aresilient deformable material that will return to the position whenmodule 14 is withdrawn from mounting location 38.

For example, in FIG. 31, a fiber optic splitter module 14 is shownpartially inserted within chassis 12 prior to connectors 118 of splittermodule 14 having contacted shield 182 of chassis 12. In FIG. 32, fiberoptic splitter module 14 is shown in a position within chassis 12 withconnectors 118 of fiber optic splitter module 14 making initial contactwith shield 182 of chassis 12 to move shield 182 out of the way (a sidecross-sectional view is shown in FIG. 34). In FIG. 33, fiber opticsplitter module 14 is shown in a fully inserted position within chassis12, having moved shield 182 out of the way (a side cross-sectional viewis shown in FIG. 35).

Shield 182 is configured such that shield 182 does not engage theferrule 184 of connector 118 of splitter module 14 when connector 118contacts shield 182 to move it out of the way. Instead, outer connectorhousing 150 pushes shield 182 out of the way.

Shield 182 may be connected to chassis 12 by fasteners, or,alternatively, shield 182 may be formed integrally with chassis 12 ormounted by spot-welding or other fastening techniques.

As shield 182 is fully deflected, further insertion of module 14 bringsconnectors 118 into contact with adapters 64 and connectors 118 arereceived within front ends 68 of adapters 64. Latch 52 is deflectedinwardly as module 14 is inserted and then flexes back so that front lip50 of bulkhead 48 is captured in recess 136. Module 14 is now inposition to process and transmit signals from cable through first cable178, optical component 158 and second cable 180 within module interior114.

Referring to FIG. 35, as noted above, recess 136 between the two tabs132, 134 of latch 52 provides a certain amount of horizontal float forthe splitter module 14 within chassis 12. Front lip 50 of bulkhead 48 isallowed to move a distance of D as indicated in FIG. 35 before it makescontact with square face 140 of rear tab 134. Splitter module 14 isconfigured such that, when splitter module 14 is pulled away from front32 of chassis 12, distance D front lip 50 of bulkhead 48 travels beforecontacting square face 140 of rear tab 134 is less than the horizontalfloat (i.e., distance A) provided for adapter assembly 16, as discussedbefore.

In this manner, splitter module 14 provides a form of protection fromaccidentally disengaging connectors 118 of the module from adapterassemblies 16 at rear 28 of chassis 12. The size of recess 136 of module14 is configured such that the horizontal float of splitter module 14 isinterrupted before the adapter assembly 16 can be pulled far enoughtoward the front of chassis 12 to stop its horizontal movement andaccidentally disengage connectors 118 of module 14 from adapters 64.

FIGS. 36-39 illustrate a fiber optic wavelength division multiplexing(WDM) module 214 having features that are examples of inventive aspectsin accordance with the present disclosure. The WDM module 214 isconfigured similarly to the splitter module 14 of FIGS. 20-30 in certainaspects. For example, the WDM module 214 is configured to be insertedwithin the chassis 12 in a similar manner as module 14. However, the WDMmodule 214 houses a fiber optic multiplexer/demultiplexer 358 and thefeatures of the module 214 are configured for supporting themultiplexer/demultiplexer 358 and integrating into a telecommunicationssystem. As will be discussed in detail, the WDM module 214 includesinternal features for housing the multiplexer/demultiplexer 358 androuting and managing cables to and from the multiplexer/demultiplexer358 and external features for integrating the multiplexer/demultiplexer358 into a telecommunications assembly including a chassis 12, such asthe telecommunications assembly 10 of FIGS. 1-7.

Referring to FIG. 38, the WDM module 214 is shown in an explodedorientation. WDM module 214 includes a module housing 292 that includesa main housing portion 294 and a removable cover 296. The main housingportion 294 is illustrated separately in FIGS. 40-45 and the cover 296is illustrated separately in FIGS. 46-48. The module housing 292 isconfigured to house a multiplexer/demultiplexer chip 358 therewithin formultiplexing/demultiplexing signals that are input and output throughconnectors 318 of the module 214. The module housing 292 includes acable exit 320 for relaying fiber signals to customers.

The WDM module 214 includes a number of cable management/routingfeatures as will be described in further detail below. One of the cablemanagement features includes the fiber retainer 360 that is removablymounted to the main housing portion 294 of the module housing 292, asshown in FIG. 38. As also shown in FIG. 38, a label 361 includingindicia relating to the module 214 may be mounted to the cover portion296 of the housing 292.

Still referring to FIG. 38, the main housing portion 294 defines a firstsidewall 298 extending between a top wall 300, a bottom wall 302, a rearwall 304, and a front wall 306. Removable cover 296 defines a secondsidewall 308 of the module housing 292 and closes off the open side ofmodule main housing portion 294.

Cover 296 is mounted to main housing portion 294 by fasteners throughfastener holes 309 in the cover 296 and fastener mounts 310 defined onmain housing portion 294. Cover 296 extends beyond the first sidewall298 to form a top mounting flange 244 and a bottom mounting flange 246of the WDM module 214, similar to the splitter module 14 (see FIGS. 36and 37). As discussed previously for chassis 12, the bottom flange 246and the corresponding slot 42 on chassis 12 are smaller in size than topflange 244 and the corresponding top slot 40 on chassis 12. Bottom slot42 is sized so that, while bottom flange 246 may be received within slot42, the larger top flange 244 will not fit. This ensures that the WDMmodules 214 are positioned within front opening 30 of the chassis 12 ina particular desired orientation to be correctly coupled to adapterassemblies 16 mounted adjacent rear 28 of chassis 12 at each mountinglocation 38.

Rear wall 304 of main housing portion 294 includes a curved portion 312configured to provide bend radius protection to cables within interiorof the module 214. Similar to module 14, the rear wall 304 of mainhousing 294 includes an inset portion 316 and a pair of fiber opticconnectors 318 positioned at the inset portion 316. The connectors 318protrude rearwardly from rear wall 304 for mating with fiber opticadapters 64 of adapter assemblies 16 mounted within chassis 12.

As shown in FIGS. 40-43, the front wall 306 of the module main housing294 is angled with regard to front opening 30 of chassis 12, which mayaid in the direction of cables exiting the WDM module 214 toward adesired location. In other embodiments, front walls could be madegenerally parallel to front 32 of chassis 12 within the scope of thepresent disclosure.

As noted above, the embodiment of the WDM module 214 illustratedincludes one cable exit 320 extending from front wall 306 of module mainhousing 294. The cable exit 320 is slidably mounted to main housing 294of the WDM module 214 and is captured by the cover 296 when cover 296 ismounted to main housing 294. The cable exit 320 defines a protrudingrear lip 322 that is slidably inserted into a slot 324 defined around afront aperture 326 for accommodating the cable exit 320. Cover 296 alsoincludes a slit 328 that receives the rear lip 322 of the cable exit 320to capture the cable exit 320. The cable exit 320 permitstelecommunications cables within module 214 that have beenmultiplexed/demultiplexed to be directed outside of module 214. Thecable exit 320 is preferably sized thin enough to fit within the profileof the WDM module 214, similar to splitter module 14, as shown in FIG.25, to preserve the density of the telecommunications assembly.

Referring to FIGS. 40-45, the main housing 294 includes an integrallyformed flexible latch 252 (i.e., cantilever arm) that is adapted toengage a portion of chassis 12 to hold module within front opening 30 ofchassis 12. Flexible latch 252 also deflects to permit withdrawal ofmodule from chassis 12. The flexible latch 252 of the module 214 isconstructed similarly to that of module 14 and operates in a similarmanner for insertion and removal of the module from chassis 12. As inmodule 14, the latch 252 of module 214 includes a finger grip tab 330, afront latching tab 332 and a rear latching tab 334 that cooperate withthe bulkhead 48 at the mounting location 38 of the chassis 12. The WDMmodule 214 also includes a fixed grip tab 344, similar to module 14,opposing and adjacent to flexible latch 252 to aid removal of module 214from chassis 12. Fixed grip tab 344 is preferably positioned on module214 opposite latch 252 so that a user may apply opposing force on latch252 and fixed grip tab 344 to securely grasp module 214 and remove itfrom chassis 12 with two adjacent fingers of the hand. The insertion ofthe WDM module 214 into chassis 12 is similar to that of module 14 andis described above with respect to FIGS. 31-35.

Still referring to FIGS. 40-45, within interior of main housing 294,module 214 includes a first radius limiter 346 adjacent curved portion322 of rear wall 304 of main housing 294. The WDM module 214 includes asecond radius limiter 348 adjacent front wall 306 of housing near thecable exit 320. A third radius limiter 349 is located adjacent the frontwall 306 below the second radius limiter 348. As will be discussed infurther detail below, the radius limiters 346, 348, 349 providebend-protection to fiber cables within the module 214 while providingcable management/routing functionality.

Adjacent bottom wall 302 of main housing 294 within interior are locateda first guide 364 and a second guide 366 for placement of themultiplexer chip 358 within the module 214. A third guide 368 is locatedadjacent the first radius limiter 346. The first radius limiter 346defines a curved wall 415. The curved wall 415 includes a first end 417and a second end 419. The first and second ends 417, 419 of the curvedwall 415 also act as guides in positioning the multiplexer chip 358within the main housing 294. The first, second, and third guides 364,366, 368 and the ends 417, 419 of the curved wall 415 of the firstradius limiter 346 form a frame structure around the chip 358 forcorrectly positioning the multiplexer chip 358 within the interior ofthe main housing portion 294. As shown in FIGS. 38 and 39, once themultiplexer chip 358 is placed within the guides, the chip 358 is heldwithin the module 214 against the first sidewall 298 by the removablecover 296.

The first sidewall 298 of the main housing 294 includes a first notch370 for accommodating fiber cables that may extend underneath themultiplexer chip 358. Once the chip 358 is placed within the mainhousing 294, the notch 370 creates a space between the chip 358 and thefirst sidewall 298 and accommodates any cables routed between the chip358 and the first sidewall 298.

Still referring to FIGS. 40-45, the module main housing 294 alsoincludes integrally formed crimp holders 374 (e.g., slots) adjacentfront wall 306 of housing 294 in between the second and third radiuslimiters 348, 349. Crimp elements 376 (see FIGS. 38-39) crimped to theends of cables that are multiplexed/demultiplexed by the chip 358 areslidably received into crimp holders 374. Crimp elements 376 definesquare flanges 375 between which is defined a recessed portion 377. Thecrimp holders 374 include complementary structure to the crimp elements376 such that once the crimp elements 376 are slidably inserted into thecrimp holders 374, the crimp elements 376 are prevented from moving in alongitudinal direction due to the flanges 375. Once slidably inserted,crimp elements 376 are held in place by the cover 296 that is mounted tomodule main housing 294. In the embodiment shown, there are four crimpholding slots 374, each one being able to accommodate up to four crimpelements 376. Other numbers are possible. Other complementary shapesbetween the crimp elements and the crimp holding slots are also possibleto provide a slidable fit and to prevent axial movement of the crimpelements once inserted into the crimp holders.

Now referring back to FIGS. 36-39, as in module 14, connectors 318 ofWDM module 214 are slidably inserted into opposing slots 354 formed inapertures 356 at the rear wall 304. Connectors 318 project out from rearwall 304 at inset portion 316 of rear wall 304. Connectors 318 of WDMmodule 214 are similar in construction to connectors 118 of the splittermodule 14. Connectors 318 of the WDM module 214 may function both asinput connectors and output connectors since the WDM module 214 isconfigured to both demultiplex signals coming in and multiplex signalsgoing out of the connectors 318. The main housing 294 includes areinforcement structure 311 extending from the sidewall 298 of the mainhousing 294. The reinforcement structure 311 aligns and fits into arecess 491 defined on the sidewall 308 of the cover 296 (see FIGS. 46and 48) when the main housing 294 and cover 296 are assembled together.

FIGS. 46-48 illustrate the cover 296 of the WDM module 214. The cover296 is configured to be fastened to the module main housing portion 294.As discussed previously, once mounted, the cover 296 defines differentsized flanges 244, 246 for slidably inserting the module 214 within thechassis 12 and for correctly orienting the module 214 with respect tothe chassis 12.

The cover 296 defines a tab 373 adjacent the front end 371 thereof. Thetab 373 is slidably inserted within a recess 431 defined at the frontwall 306 of the main housing portion 294 (see FIGS. 38 and 41) tocorrectly orient the cover 296 with respect to the main housing portion294. As will be described below, the recess 431 may also be used as asignal input location for using the module 214 as a front-input moduleif desired (see FIGS. 49-56). As such, terminated fiber optic cables maybe accommodated by and received within the recess 431. In the embodimentshown, two cables may be received within the recess 431 in a stackedarrangement. The tab 373 that is normally used to cover the recess 431when the module is used a rear-input module, may be cut or trimmed to anappropriate length for accommodating the terminated cables entering themodule 214 when the module 214 is used as a front-input module.

As shown in FIG. 46, the tab 373 may include a stepped configurationwith two tiers. The step line 492 indicates the location where the tab373 may be broken off or cut off to allow enough room for one inputcable 493. If one input cable 493 needs to be accommodated, the tab 373is cut at the step line 492 (see FIGS. 53-56). If two input cables 493need to be accommodated, the tab 373 must be cut at its base 494 tocreate enough spacing (see FIGS. 49-52). It should be noted that the tab373 and the recess 431 may be arranged and configured to accommodate anynumber of input cables 493. The stepped configuration of the tab 373serves the purpose of identifying the cut location for accommodating asingle input cable 493 and also makes it possible to still use theremainder of the tab 373 to cover the recess 431 if only one input cable493 is being used.

When the module 214 is used as a front-input module, as will bediscussed below, the apertures 356 that are normally used to receivefiber optic connectors 318 may be covered by insert pieces 495 (seeFIGS. 51, 52, 55, and 56).

As shown in FIG. 46, the cover 296 also includes protruding portions 379defined around the periphery and slots 381 defined between theprotruding portions 379 that intermate with corresponding structureslocated around the periphery of the main housing 294 for correctlyplacing the cover 296 onto the main housing 294.

As shown in FIG. 46, the cover 296 defines a second notch 372 on thesecond sidewall 308. The second notch 372 is configured to accommodatethe multiplexer chip 358 once the cover 296 is mounted on the mainhousing portion 294. The cover 296 also defines slots 383 on the secondsidewall 308 for receiving the structures of the main housing portion294 that define the crimp holders 374 thereinbetween. The slots 383 arelocated in a notched area 385. This third notch 385 accommodates thearea of the main housing portion 294 with the crimp holders 374.

The WDM module 214 is shown in FIG. 39 with the cover 296 and the fiberretainer 360 removed from the main housing portion 294 to illustrate theinternal components and to illustrate the cable routing.

One sample cable routing arrangement is shown in FIG. 39. Others arepossible. As shown in FIG. 39, a first cable 378 extends from one of theconnectors 318 toward and around the second radius limiter 348. From thesecond radius limiter 348, the first cable 378 extends downwardly towardthe third radius limiter 349 and around the first guide 364 toward therear of the module 214. As the cable 378 extends from the first guide364, the cable 378 is positioned in a space 400 defined between thebottom wall 302 and the multiplexer chip 358. After going around thesecond guide 366 and upwardly, the first cable 378 goes around the firstradius limiter 346 and toward the front of the module 214. The firstcable 378 is, then, led around the second radius limiter 348 and thethird radius limiter 349. From the third radius limiter 349, the firstcable 378 enters the multiplexer chip 358. The fiber optic signals thatare input into the multiplexer 358 are demultiplexed and split into thedifferent wavelengths that are carried by separate second cables 380 forservice to different customers.

Once demultiplexed, second cables 380 extend from the chip 358 and arelooped around the first radius limiter 346 and then extend underneaththe chip 358 before they are looped again around the first radiuslimiter 346. The first notch 370, as discussed previously, accommodatesthe cables 380 going underneath the chip 358 between the sidewall 298 ofthe main housing 294 and the chip 358. After the second cables 380 havebeen looped around the first radius limiter 346 again, they extendtoward crimp holders 374. From crimp holders 374, cables crimped to theother ends of the crimps exit the module through exit as customer outputpigtails 401.

As noted above, the routing of the fiber optic cables within module 214as shown in FIG. 39 is only one example and other ways of routing thecables within the module are possible.

As shown in FIG. 38, a fiber retainer 360 may be placed on the mainhousing portion 294 to keep cables 380 wrapped around the first radiuslimiter 346. The fiber retainer 360 is planar and includes asemicircular shape to match the contour of the curved portion 312 of therear wall 304 of the main housing 294. The fiber retainer 360 includesthree tabs 403 positioned around the periphery. The three tabs 403 areplaced within slots 405 formed around the curved portion 312 of the rearwall 304. The fiber retainer 360 includes a semicircular opening 407which accommodates a portion of the first radius limiter 346 thatprotrudes through the opening 407. When the fiber retainer 360 is placedon the main housing portion 294, it lies flush with the main housingportion 294 and is held thereagainst by the cover 296.

It will be noted that the multiplexing chip 358 provides a two-waysignal path for the signal going through it. Input signals input throughthe connectors 318 are demultiplexed and are split into differentwavelengths and signals coming from the customers are multiplexed andcombined into a single signal to be carried on a single fiber that isoutput also through the connectors 318. For inputting and outputtingsignals, an outside cable (not shown) terminated by a connector isoptically connected to a connector 318 of the module 214 through anadapter 64 of the adapter assembly 16. This connection is established bythe slidable insertion of the WDM module 214 into the chassis 12.

According to one embodiment, the WDM module 214 may house a 1×4 densewavelength division multiplexing chip. According to another embodiment,the WDM module may house a 1×8 dense wavelength division multiplexingchip. According to another embodiment, the WDM module may house a 1×16dense wavelength division multiplexing chip. In another embodiment, themodule may house a coarse wavelength division multiplexing chip. Othertypes of multiplexer chips are also contemplated.

According to one embodiment, an overlay filter chip may be used withinthe module 214. Such a chip may be positioned in the space locatedbetween the bottom wall 302 of the main housing 294 of the module 214and the multiplexer chip 358.

Referring now to FIGS. 49-56, the WDM module 214 of FIGS. 36-48 isillustrated as configured to be a front-input module, wherein the signalto be multiplexed/demultiplexed by the optical component 358 within themodule 214 enters and exits the module at the front side thereof. FIGS.49-52 illustrate the WDM module 214 configured as having two frontsignal input locations 496, wherein the signal input cables 493 areconfigured in a stacked arrangement extending from the first sidewall298 toward the second sidewall 308 defined by the cover 296 of themodule 214. FIGS. 53-56 illustrate the WDM module 214 configured ashaving one front signal input location 496.

As described previously, the cover 296 used to cover the module 214defines a single tab 373 adjacent the front end 371 thereof. The tab 373is normally slidably inserted within the recess 431 defined at the frontwall 306 of the main housing portion 294 to correctly orient the cover296 with respect to the main housing portion 294. However, when themodule 214 is desired to be used as a front-input module, the terminatedfiber optic cables 493 may be accommodated by and received within therecess 431. The tab 373, which is normally used to cover the recess 431when the module 214 is used a rear-input module, may be cut or trimmedto an appropriate length for accommodating the terminated cables 493entering the module 214. As discussed above, the tab 373 defined on thecover 296 may include a stepped configuration with two tiers. The stepline 492 indicates the location where the tab 373 may be broken off orcut off to allow enough room for one input cable 493. If one input cable493 needs to be accommodated, the tab 373 is cut at the step line 492(see FIGS. 53-56). If two input cables 493 need to be accommodated, thetab 373 must be cut at its base 494 to create enough spacing (see FIGS.49-52).

It should be noted that the tab 373 of the cover 296 and the recess 431of the module main housing 294 may be arranged and configured toaccommodate any number of input cables 493. Also, in differentembodiments, the tab of the cover and the recess of the module mainhousing may be reversed so that the tab is provided on the housing andthe recess is provided on the cover.

FIG. 57 illustrates an exploded view of an example front inputconnection 500 for inputting a signal into the module 214 of FIGS.49-56. FIG. 58 illustrates the input connection 500 in a fully assembledconfiguration. As shown, each input connection 500 includes a boot 502that mates with a crimp element 504. The crimp element 504 defines acircumferential notch 506 (i.e., recessed portion). The circumferentialnotch 506 is slidably inserted into the recess 431 defined by the frontwall 306 of the module main housing 294. The crimp elements 504 of theinput connections 500 are captured by the cover 296 when the cover 296is mounted on the module main housing 294.

As discussed previously, when the module 214 is used as a front-inputmodule, the apertures 356 that are normally used to receive fiber opticconnectors for inputting the input signal may be covered by insertpieces 495. See FIGS. 51, 52, 55, and 56 for examples of insert pieces.

Referring now to FIGS. 59-62, another embodiment of a module 600 havinga front-input configuration is illustrated. The module 600 illustratedin FIGS. 59-62 is a fiber optic splitter module. The fiber opticsplitter module 600 is similar to the fiber optic splitter module 14illustrated in FIGS. 20-30, except that the fiber optic splitter module600 is configured as a front-input module. Otherwise, the fiber opticsplitter module 600 is configured similarly to the module 14 of FIGS.20-30 and is configured to be inserted within the chassis 12 in asimilar manner as the previously described modules 14, 214.

It should be noted that the fiber optic splitter module 600 illustratedin FIG. 59 is simply one example of a telecommunications moduleaccording to the present disclosure that includes front signal inputlocations. As described above, the front-input configuration can be usedon other types of modules described herein such as the WDM module 214(FIGS. 49-56) as noted previously. When the telecommunications modulesdescribed herein are configured as front-input modules, input signalsare received into the module housing from the front of the housing,rather than the rear of the housing.

In the embodiment of the module 600 shown in FIGS. 59-62, there are twoinput locations 602 for accommodating two terminated input cables 604.The front wall 606 of the module housing 608 defines two recesses 610that are sized to accommodate the terminated cables 604. As shown inFIG. 59, the cover 612 includes two tabs 614 that are normally used tocover the recesses 610 located on the front wall of the module housing608. When the module 600 is used as a front-input module, the tabs 614are cut to appropriate length to accommodate the cables 604 and capturethe terminations within the recesses 610. In the embodiment of themodule 600 shown in FIGS. 59-62, the front input cables 604 are arrangedin a side by side configuration along a direction extending from the top616 of the module 600 toward the bottom 618 of the module 600.

It should be noted that the front input location 602 may also beconfigured to receive input cables 604 in a stacked arrangement along adirection extending from the first sidewall 620 of the module 600 towardthe second sidewall 622 defined by the cover of the module 600, asdescribed above for the WDM module 214 of FIGS. 49-56. Please see FIGS.63-64 for a fiber optic splitter module 700 that includes such a stackedfront-input arrangement. As discussed previously, when using a stackedarrangement, a single tab may be used to cover the recess, wherein thetab may be cut or broken at an appropriate location.

The fiber optic splitter module 600 of FIGS. 59-62 may use a front inputconnection similar to that used on the WDM module 214 of FIGS. 49-56,the front input connection 500 shown in detail in FIGS. 57-58.

Now referring to FIG. 62, the right side view of the fiber opticsplitter module 600 of FIG. 59 is illustrated, wherein the module 600 isshown without the cover to illustrate the routing of a fiber optic cablewithin module 600 when the module 600 is used as a front-input module.According to a sample routing, a first input cable 604 extends from thefront input location 602 around a radius limiter 624 (similar to secondradius limiter 148 of FIG. 29) toward the rear 626 of the module 600. Atthe rear 626 of the module 600, the first cable 604 is looped around aradius limiter 628 (similar to first radius limiter 146 of FIG. 29) inthe form of a spool. From the spool 628, the first cable 604 extendstoward the front 630 of the module 600 and around the radius limiter 624downwardly toward the optical component 632, mounted within modulehousing.

Optical component 632 within the module 600, as previously discussed,may be a splitter or a fan-out or another type of optical component. Inthe embodiment shown, optical component 632 is a fiber optic splitterthat splits the signal of a single strand to a plurality of secondarysignals. In another embodiment, the first input cable 604 may be amulti-strand fiber cable with a plurality of strands of optical fiberand optical component 632 may be a fanout to separate the individualstrands into each of a plurality of second cables.

First input cable 604 is received into the optical component 632 and thesignal is split into a plurality of signals carried by a plurality ofcables 634 that are bundled into a second cable 636. Second cable 636extends from optical component 632 toward the rear 626 of the module 600and is looped again all the way around first radius limiter 628 beforeheading toward crimp holders 638. A fiber retainer 640 may be used, asshown in FIG. 59, to keep the fiber optic cable 636 around the spool628.

The bundled second cable 636 is separated into individual cables 634 asit leaves the spool 628. The individual cables 634 are crimped to outputcables 642 at the crimp holders 638 and the output cables 642 exit themodule through module exits 644.

It should be noted that the routing of the fiber optic cables withinmodule 600 as shown in FIGS. 59 and 62 is only one example and otherways of routing the cables within the module 600 are possible.

FIGS. 63-64 illustrate another embodiment of a fiber optic splittermodule 700 having features that are examples of inventive aspects inaccordance with the present disclosure. Similar to the WDM module 214illustrated in FIGS. 49-56, the fiber optic splitter module 700 includesfront signal input locations 702 that are configured in a stackedarrangement along a direction extending from the first sidewall of themodule 700 toward the second sidewall defined by the cover of the module700. In FIGS. 63-64, the fiber optic splitter module 700 is shown incombination with a prior art fiber optic adapter module 710 configuredto hold a plurality of fiber optic adapters.

As described previously, when the input cables are in a stackedarrangement, a tab of the cover, which is normally used to cover therecess when the module is used a rear-input module, may be cut ortrimmed to an appropriate length for accommodating the terminated cablesentering the module 700. Similar to the cover 296 shown in FIG. 46, thetab may include a stepped configuration with two tiers. The step lineindicates the location where the tab may be broken off or cut off toallow enough room for one input cable. If enough spacing for one inputcable is needed, the tab may be cut at the step line (similar to thestep line 492 shown in FIGS. 53-56 for the WDM module 214). If enoughspacing is needed to accommodate both input cables, the tab may be cutat the base of the tab (similar to that shown in FIGS. 49-52 for the WDMmodule 214). It should be noted that the tab of the cover and the recessof the module may be arranged and configured to accommodate any numberof input cables. Also, in different embodiments, the tab of the coverand the recess of the module housing may be reversed so that the tab isprovided on the housing and the recess is provided on the cover.

As discussed previously, when the module is used as a front-inputmodule, the apertures that are normally used to receive fiber opticconnectors for inputting the input signal may be covered by insertpieces. See FIGS. 51, 52, 55, and 56 for examples of insert pieces 495.

The fiber optic splitter module 700 of FIGS. 63-64 may use a front inputconnection similar to that of the WDM module 214 of FIGS. 49-56 and thefiber optic splitter module 600 of FIGS. 59-62. A front input connection500 is shown in detail in FIGS. 57-58. The fiber optic splitter module700 of FIGS. 63-64 may also follow a similar cable routing configurationas the routing used in the fiber optic splitter module 600 of FIGS.59-62 described above.

The above specification, examples and data provide a completedescription of the manufacture and use of the disclosure. Since manyembodiments of the disclosure can be made without departing from thespirit and scope of the inventive aspects, the inventive aspects residesin the claims hereinafter appended.

What is claimed is:
 1. A telecommunications module comprising: a housing including a main housing portion and a removable cover cooperatively defining an interior, the main housing portion defining a first sidewall, a front wall, a rear wall, a top wall, and a bottom wall, the cover defining a second sidewall of the housing when mounted on the main housing portion to close off the interior; the main housing including at least one signal output location defined on the front wall; an optical component located within the interior, the optical component configured to receive a fiber optic input signal coming in from a signal input location of the housing and output a fiber optic output signal going toward the signal output location defined on the front wall of the main housing, wherein the telecommunications module is configured such that the signal input location can be selected to be on either the front wall or the rear wall of the main housing; the cover defining a protrusion extending from the second sidewall toward the main housing portion, the protrusion received within a recess defined on the front wall of the main housing portion when the cover is mounted on the main housing portion; wherein, if the signal input location is desired to be on the front wall, the protrusion is selectively breakable to expose the recess defined on the front wall of the main housing portion, the recess defining a signal input location.
 2. A telecommunications module according to claim 1, wherein the protrusion includes two breakable portions separated by a break line, the breakable portions include a base portion and a tip portion, wherein, if one input cable carrying a fiber optic input signal is desired to enter the main housing, the tip portion is adapted to be selectively broken off and if two input cables carrying fiber optic input signals are desired to enter the main housing, the protrusion is selectively broken off at the base portion to remove the entire protrusion.
 3. A telecommunications module according to claim 1, wherein, when the signal input location is selected to be on the rear wall of the housing, the signal input location is defined by at least one fiber optic connector extending from the rear wall of the main housing toward an exterior of the housing.
 4. A telecommunications module according to claim 1, wherein the optical component is a fiber optic splitter that splits the fiber optic input signal into a plurality of the fiber optic output signals.
 5. A telecommunications module according to claim 1, wherein the optical component is an optical wavelength division multiplexer/demultiplexer.
 6. A telecommunications module according to claim 1, wherein the main housing includes a flexible cantilever arm extending from the front wall of the main housing for providing a snap fit connection with a piece of telecommunications equipment.
 7. A telecommunications module according to claim 1, wherein the main housing portion includes two cable exits projecting outwardly from the housing, the two cable exits defining signal output locations.
 8. A telecommunications module according to claim 1, wherein the main housing portion includes a cable management structure in the form of a spool for guiding a cable carrying the fiber optic output signal toward the signal output location.
 9. A telecommunications module comprising: a housing including a main housing portion and a removable cover cooperatively defining an interior, the main housing portion defining a first sidewall, a front wall, a rear wall, a top wall, and a bottom wall, the cover defining a second sidewall of the housing when mounted on the main housing portion to close off the interior; the main housing including at least one cable exit positioned on the front wall of the main housing portion, the cable exit including an outer extension beyond the front wall; at least one fiber optic connector that protrudes from rear wall of the main housing portion, the fiber optic connector adapted to be inserted into a fiber optic adapter when the module is inserted into a piece of telecommunications equipment; an optical component located within the interior, the optical component configured to receive a fiber optic input signal coming in through the fiber optic connector located at the rear wall and output a fiber optic output signal toward the cable exit located on the front wall of the main housing; and the cover defining a protrusion extending from the second sidewall toward the main housing portion, the protrusion received within a recess defined on the front wall of the main housing portion adjacent the cable exit when the cover is mounted on the main housing portion.
 10. A telecommunications module according to claim 9, wherein the protrusion of the cover is selectively breakable to expose the recess defined on the front wall of the main housing, wherein the recess is selectively usable as a signal input location if the at least one fiber optic connector located on the rear wall is not used as a signal input location.
 11. A telecommunications module according to claim 9, wherein the optical component is a fiber optic splitter that splits the fiber optic input signal into a plurality of the fiber optic output signals.
 12. A telecommunications module according to claim 9, wherein the optical component is an optical wavelength division multiplexer/demultiplexer.
 13. A telecommunications module according to claim 9, wherein the main housing includes a flexible cantilever arm extending from the front wall of the main housing for providing a snap fit connection with the piece of telecommunications equipment.
 14. A telecommunications module according to claim 9, wherein the module includes two fiber optic connectors protruding from rear wall of the main housing portion.
 15. A telecommunications module according to claim 9, wherein the main housing portion includes a cable management structure in the form of a spool for guiding a cable carrying the fiber optic output signal toward the cable exit.
 16. A method of using a telecommunications module comprising: providing a module housing including a main housing portion and a removable cover cooperatively defining an interior, the main housing portion defining a first sidewall, a front wall, a rear wall, a top wall, and a bottom wall, the cover defining a second sidewall of the housing when mounted on the main housing portion to close off the interior; providing a signal output location defined on the front wall; inserting an optical component into the housing, the optical component configured to receive a fiber optic input signal coming in from a signal input location of the housing and output a fiber optic output signal going toward the signal output location defined on the front wall of the main housing; providing a protrusion on the cover, the protrusion extending from the second sidewall toward the main housing portion, the protrusion configured to be received within a recess defined on the front wall of the main housing portion when the cover is mounted on the main housing portion, the recess defining the signal input location; breaking at least a portion of the protrusion on the cover such that the protrusion does not completely cover the recess when the cover is mounted on the main housing portion.
 17. A method according to claim 16, wherein the protrusion includes two breakable portions separated by a break line, the breakable portions include a base portion and a tip portion, wherein the method further comprises breaking the tip portion if one input cable carrying a fiber optic input signal is desired to enter the main housing or breaking the protrusion at its base to expose the entire recess if two input cables carrying fiber optic input signals are desired to enter the main housing.
 18. A method according to claim 16, wherein the optical component is a fiber optic splitter that splits the fiber optic input signal into a plurality of the fiber optic output signals.
 19. A method according to claim 16, wherein the optical component is an optical wavelength division multiplexer/demultiplexer.
 20. A method according to claim 16, wherein the main housing portion includes a cable management structure in the form of a spool for guiding a cable carrying the fiber optic output signal toward the signal output location. 